1. Field of the Invention
The present invention relates to a nonaqueous electrolyte battery, a battery pack equipped with a nonaqueous electrolyte battery, and a vehicle having a battery pack mounted thereto.
2. Description of the Related Art
Along with miniaturization of, for example, personal computers, video cameras and portable telephones, nonaqueous electrolyte batteries have been put to practical use and widely spread in the fields of information relevant devices and communication devices as the power sources because they have high energy density. Meanwhile, in the field of vehicles, it is desired to develop electric motor vehicles as quickly as possible because of environmental and resource problems and studies are being made also as to nonaqueous electrolyte batteries as the power sources of these electric motor vehicles.
It is demanded of these secondary batteries used for the power source of these electric motor vehicles to have a high energy density and, specifically, to have a high discharge capacity per unit weight or unit volume. Then, even in the case where large current is input in a moment to recover the kinetic energy in the decelerating stage as the electric power, it is demanded of these secondary batteries to have the ability of charging efficiently. In short, the secondary batteries used as the power sources of electric motor vehicles are desired not only to have a large capacity but also to have good performance of inputting power in a short time. Also, the secondary batteries are required to exhibit a large output, i.e., to be capable of an instant discharge of a large current when, for example, the vehicles start, abruptly move or abruptly accelerate.
It is disclosed in JP-A 2005-72008 (KOKAI) that a negative electrode active material formed of vanadium oxide, represented by LixMyVzO2+d, has a pore volume per unit weight of 10−3 to 0.8 cc/g, the pores having a diameter of 0.1 to 10 μm.